I need help wrapping my head around wire sizeing and need help with a couple questions.. why is it recommended to run a large guage wire such a 10 guage through a fuse such as a 3 or 5 amp size. I know larger diameter wire can carry more voltage but seems that going through a fuse with a filament the size of a couple wire strands would choke the power down and restrict the flow of electricity.
Another question, why run 10 guage to a unit with 22 guage supply at the unit?
I was having voltage drop on my humminbird units so I decided to run a dedicated fuse block just for electronics and ran an 8 guage wire to my fuse block and ran 10 guage to all my electronics. I did this because that's what is recommended, but why exactly? The 8 guage I ran may have been a little over kill but it's what I had on hand when I upgraded the trolling motor wiring to 6 guage.

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